Summer is a time for looser schedules, longer days, more time outdoors, and more frequent travel. While these may be things you’ve been looking...

Summer is a time for looser schedules, longer days, more time outdoors, and more frequent travel. While these may be things you’ve been looking forward to all year (I know I have!), they could cause annoying changes to your monthly cycle.

Dr. A. Nicky Hjort, M.D., OB-GYN, defines a “regular” cycle as usually occurring between twenty-one and thirty-five days, hence the “average” twenty-eight day cycle; usually with a flow for three to five days, soaking a pad or tampon—but not both—every two to three hours; and usually with a day or two of heavier flow. But even a cycle that functions like clockwork can be thrown off with some of these all-too-common summertime symptoms. (And of course, if you’ve considered these possibilities and something still seems off, visit your doctor for her opinion.)

01. Too Much Exercise

Dr. John Fejes, MD, FACOG, and an OB-GYN at the Community Hospital of Monterey Peninsula, says becoming more active in the summer months could cause a change in your cycle. Everything in your body is connected—your hormones, brain, and reproductive system. If you’ve started working out more often or more aggressively, and your cycle is delayed, it may be wise to scale back. Your body may be trying to tell you you’ve pushed it too far, and it doesn’t have the resources it needs to keep up with all your systems. When done in moderation, however, exercise can lessen the pain that comes with that time of the month.

02. Significant or Rapid Weight Loss or Gain

It’s no secret that many women start trying to achieve their “summer body” this time of year. As much as this might mean working out more, it often goes hand in hand with dieting, whether eating less or simply eating clean. Whatever the case may be, when it comes to surprise weight changes, Aunt Flo is the first to notice. If you gain weight, an abnormal period often happens next. It might be heavy one month and absent the next. Rapid weight loss produces a similar effect, causing a light or missed period. It comes down to the ability of fat cells to produce extra estrogen. When there’s too much or too little, a hormonal imbalance occurs and causes irregular or missed periods. Getting your body back to your healthy weight will help regulate your cycle.

03. Stressful Life Transitions

This time of year is full of weddings, graduations, moves, and starting new jobs—and big life transitions just happen to be one of the biggest causes of stress. The brain plays a vital role in your cycle, so if you’re stressed or sick, it can prompt hormones to delay your ovulation. If you chart your cycle, you’ll notice that your fertile days are delayed, which means your period will be late too.

04. Warm-Weather-Prone Infections

Dr. Fejes says that “weather changes can lead to frequent yeast vaginitis and bacterial infections,” which can cause irregular cycles. To keep fungus- and infection-free in warmer months, he recommends not douching and wearing loose cotton underwear. Stay hydrated to keep your system clear, and don’t stay in a wet bathing suit after you’re done swimming. Dr. Hjort also stresses the importance of always wiping front to back to prevent bacteria getting where they shouldn’t be.

05. Going On or Off Hormonal Medications

Over the last few years, there has been a growing trend in women using hormone medications to pause their periods so that it doesn’t interfere with an upcoming vacation, wedding, or other special events. One method involves skipping the placebo pills in a birth control pack or temporarily taking progesterone to delay the uterine lining from shedding. Coming on or off of hormones can lead to a condition called “temporary PCOS,” aka polycystic ovarian syndrome, when the cycle may be delayed for weeks or even months.

Getting rid of your period (even if only temporarily) to make the most of your summer travels may sound awesome, but we wouldn’t recommend it. As Dr. Lara Briden, ND, author of Healthy Hormone Blog, explains, “A real period is the end result of a series of important hormonal events including ovulation and the production of estrogen and progesterone. To speak of the bleed without mentioning hormones is nonsensical to me.”

Age-old wisdom tells us there are seasons in life, and these are worthy of celebration. Knowing which lifestyle changes may cause a temporary shift in your cycle means not freaking out when something isn’t really wrong—and being able to recognize when there truly is cause for concern.